1. Field of the Invention
The present invention relates to locks for doors that open vertically, such as garage doors, rollup doors and overhead doors. More specifically, the present invention relates to electrically controlled locks for vertical doors.
2. Description of Related Art
Doors that open vertically are widely used in self-storage centers, as garage doors and as loading and access doors. Vertical doors include various types of vertically sliding and rollup doors that are typically provided with horizontal corrugations allowing the door to bend to a horizontal position or form a horizontal roll above the door opening.
A typical method of locking vertical doors in self-storage installations uses a latch attached to the vertical door. The latch includes a sliding latchbolt that extends horizontally outward from the side of the vertical door and through the adjacent vertical door guide or doorframe. When extended, the latchbolt prevents the door from being lifted. To prevent the latch from being withdrawn, a key operated padlock is typically attached between the body of the latch and the latchbolt, holding the latchbolt in the latched position.
To remove the padlock, the self-storage customer is provided with a key. When the key is lost, or the storage area is rented to another customer, the key must be replaced and/or the lock must be changed. This represents an ongoing problem due to both cost and the labor time required. Locks and keys must also be changed when a customer has failed to pay applicable storage fees.
These difficulties have created a demand for electrically controlled vertical door locks. Such locks may be operated by a keypad, a magnetic stripe card, an RFID tag that sends a coded signal when proximate an RFID reader or by other electrically based security systems. Although sophisticated electrically controlled locks may be modified for vertical door use, there exists a need for a low cost electrically controlled lock for vertical doors.
One design difficulty in electrifying the simple mechanically operated sliding latchbolt design described above is that the latch mechanism and lock are attached to the vertical door. The vertical motion of the door makes it difficult and expensive to supply electrical power to a latch mechanism that must move whenever the door is opened or closed.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a low cost, simple and reliable vertical door locking system that electronically controls access to a secure area.
Another object of the present invention is to provide a vertical door locking system that can be installed on existing vertical doors having conventional mechanically operated sliding latches of the type described above.
Yet another object of the present invention is to provide a vertical door locking system that is electrically operated but requires no electrical connection to the portion of the lock on the moving vertical door.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.